Process of forming tubes.



UNITED STATES Patented April *11, 1905.

PATENT OFFICE. e

LESTER C. SMITH, OF ROME, NEW YORK.

PROCESS OF FORMIING TUBES.

SPEQIFICATION forming part of Letters Patent No. '786,923, dated April11, 1905.

' Application filed August 10, 1903. Serial No. 169948.

TO all whom 't may concrn:

Be it known that I, LESTER C. SMITH, of Rome, in the county of Oneidaand State of New York, have invented certain new and useful Improvements in Processes of Forming Tubes; and I do hereby declare thatthe following is a full, clear, and exact description of the inventiou,which will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,and to the letters of reference marked thereon, which form part of thisspecification.

The object of my invention is to provide a process of forming tubes fromstrips of sheet material in four passes through rollers.

In the drawings, Figure 1 shows a transversed section of the strip ofmaterial to be operated upon. Fig. 2 shows the same at the completion ofthe first operation. Fig. 3 shows the same after the second operation.Fig. 4: shows the same after the third pperation, and Fig. 5 shows thecompleted tube after the fourth operation.

The important point to be accomplished in forming tubes by the methodherein set forth (or for that matter by any method) is to have themeeting edges of the strip so closed that any tendency to spring apartis obviated, and the meeting edges, in fact, press against each otherwith considerable pressure instead of having the tendency to springapart or separate.

In carrying out my process of forming tube the first operation consistsin turning in the edges of the strip to a circle substantially the sameas that of thecompleted tube and as indicated at a a. The secondoperation con- Sists in giving a comparatvely sharp transverse bend tothe strip through the middle and forming the middle to a circle, asindi- 'cated at b, less than that of the completed tube. The thirdoperation consists in closing the tube into a substantially oval formwith the meeting edges in the larger end of the oval. The finaloperation consists in forming the last-mentioned oval tube into acircular one. The tube thus formed Will have the edges pressing againsteach other instead of springing apart and in proper condition forsoldering or brazing the two meeting edges together toform the closedpipe.

By the process herein described a tube of the character mentioned may beformed Without the useof a mandrel or core around which to operate.

What I claim as new, and desire to secure by Letters Patent, is

The process of forming a tube from a strip of sheet material in fourOperations, which consists, first, in turning in the edges of the stripto a curvature substantially that of the i circle of the completed tube;second, in bending the strip along the middle to a curvature less thanthat of the circle of the completed tube; third, closing the tube intoan oval form with the meeting edges in the large end of the oval, and,fourth, forming the last-mentioned form into a circular form,substantially as set forth.

In witness whereof I have afi ixed my signature, in presence of twowitnesses, this 4Eth day of August, 1903.

LESTER cfsMITH.

, Witnesses:

H, J. ROWLAND, JOHN E. BIELBY.

